<template>
  <div>
    <table
      border="1"
      width="900"
      style="border-collapse: collapse"
    >
      <caption>
        购物车
      </caption>
      <thead>
        <tr>
          <th>
            <input
              type="checkbox"
              v-model="isAll"
            /> <span>全选</span>
          </th>
          <th>名称</th>
          <th>价格</th>
          <th>数量</th>
          <th>总价</th>
          <th>操作</th>
        </tr>
      </thead>
      <tbody>
        <Hero
          v-for="(obj,index) in goodList "
          :key="index"
          :obj='obj'
          :index='index'
          @add='addFn'
          @reduce='reduceFn'
          @del='delFn'
        ></Hero>
      </tbody>
      <tfoot>
        <tr>
          <td>合计:</td>
          <td colspan="5">
            {{allNum}}
          </td>
        </tr>
      </tfoot>
      <tfoot v-if="goodList.length == 0">
        <tr>
          <td colspan="6">
            没有数据了
          </td>
        </tr>
      </tfoot>
    </table>
  </div>
</template>

<script>
import Hero from './components/Hero'
export default {
  components: {
    Hero
  },
  data () {
    return {
      goodList: [
        {
          name: "诸葛亮",
          price: 1000,
          num: 1,
          checked: false,
        },
        {
          name: "蔡文姬",
          price: 1500,
          num: 1,
          checked: false,
        },
        {
          name: "妲己",
          price: 2000,
          num: 1,
          checked: false,
        },
        {
          name: "鲁班",
          price: 2200,
          num: 1,
          checked: false,
        },
      ],
    };
  },
  computed: {
    allNum () {
      return this.goodList.reduce((sum, obj) => {
        if (obj.checked === true) {
          sum += obj.price * obj.num
        }
        return sum
      }, 0)
    },
    isAll: {
      set (val) {
        this.goodList.forEach(obj => obj.checked = val)
      },
      get () {
        return this.goodList.every(obj => obj.checked == true)
      }
    }
  },
  methods: {
    addFn (ind) {
      this.goodList[ind].num++
    },
    reduceFn (ind) {
      this.goodList[ind].num > 0 && this.goodList[ind].num--
    },
    delFn (ind) {
      this.goodList.splice(ind, 1)
    }
  }
};
</script>

<style>
</style>